Zilog Z80000
Encyclopedia
The Z80000 is Zilog
's 32-bit
processor
from 1986, an expansion of its 16-bit
predecessor, the Zilog Z8000
. It includes multiprocessing
capability, a six-stage instruction pipeline
, and a 256-byte cache
. Its memory addressing system can access 4 gigabyte
s of RAM
. Described at the time as a "mainframe
on a chip", the processor is in many ways an equivalent to Intel's 80386. It can execute code written for the Z8000, but is not compatible with the Intel x86 architecture, nor is it Z80
compatible.
Sixteen general-purpose registers
of variable size are available through use of a 64-byte "register file". The processor includes a memory management unit
that provides protected memory, important for multitasking
, and virtual memory
addressing for temporary storage of RAM on a hard disk
. The processor has three methods of accessing memory:
The processor is designed to interoperate with other integrated circuit
s designed for use with the Z8000, such as the Zilog Z8070 floating-point coprocessor
.
The Z-320 was the CMOS
version of the Z80000.
Zilog
Zilog, Inc., previously known as ZiLOG , is a manufacturer of 8-bit and 24-bit microcontrollers, and is most famous for its Intel 8080-compatible Z80 series.-History:...
's 32-bit
32-bit
The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....
processor
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
from 1986, an expansion of its 16-bit
16-bit
-16-bit architecture:The HP BPC, introduced in 1975, was the world's first 16-bit microprocessor. Prominent 16-bit processors include the PDP-11, Intel 8086, Intel 80286 and the WDC 65C816. The Intel 8088 was program-compatible with the Intel 8086, and was 16-bit in that its registers were 16...
predecessor, the Zilog Z8000
Zilog Z8000
The Z8000 is a 16-bit microprocessor introduced by Zilog in 1979. The architecture was designed by Bernard Peuto while the logic and physical implementation was done by Masatoshi Shima, assisted by a small group of people. The Z8000 was not Z80-compatible, and although it saw steady use well into...
. It includes multiprocessing
Multiprocessing
Multiprocessing is the use of two or more central processing units within a single computer system. The term also refers to the ability of a system to support more than one processor and/or the ability to allocate tasks between them...
capability, a six-stage instruction pipeline
Instruction pipeline
An instruction pipeline is a technique used in the design of computers and other digital electronic devices to increase their instruction throughput ....
, and a 256-byte cache
Cache
In computer engineering, a cache is a component that transparently stores data so that future requests for that data can be served faster. The data that is stored within a cache might be values that have been computed earlier or duplicates of original values that are stored elsewhere...
. Its memory addressing system can access 4 gigabyte
Gigabyte
The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is...
s of RAM
Ram
-Animals:*Ram, an uncastrated male sheep*Ram cichlid, a species of freshwater fish endemic to Colombia and Venezuela-Military:*Battering ram*Ramming, a military tactic in which one vehicle runs into another...
. Described at the time as a "mainframe
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...
on a chip", the processor is in many ways an equivalent to Intel's 80386. It can execute code written for the Z8000, but is not compatible with the Intel x86 architecture, nor is it Z80
Zilog Z80
The Zilog Z80 is an 8-bit microprocessor designed by Zilog and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes...
compatible.
Sixteen general-purpose registers
Processor register
In computer architecture, a processor register is a small amount of storage available as part of a CPU or other digital processor. Such registers are addressed by mechanisms other than main memory and can be accessed more quickly...
of variable size are available through use of a 64-byte "register file". The processor includes a memory management unit
Memory management unit
A memory management unit , sometimes called paged memory management unit , is a computer hardware component responsible for handling accesses to memory requested by the CPU...
that provides protected memory, important for multitasking
Computer multitasking
In computing, multitasking is a method where multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for...
, and virtual memory
Virtual memory
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...
addressing for temporary storage of RAM on a hard disk
Hard disk
A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...
. The processor has three methods of accessing memory:
- compact mode – meant for small programs, could only access 64 kB (equivalent to the Z8000's non-segmented mode)
- segmented mode – 32,768 segments of 64 kB or 128 segments of 16 MB, making a total of 2 GB of accessible memory
- linear mode – direct 4 GB access
The processor is designed to interoperate with other integrated circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
s designed for use with the Z8000, such as the Zilog Z8070 floating-point coprocessor
Coprocessor
A coprocessor is a computer processor used to supplement the functions of the primary processor . Operations performed by the coprocessor may be floating point arithmetic, graphics, signal processing, string processing, or encryption. By offloading processor-intensive tasks from the main processor,...
.
The Z-320 was the CMOS
CMOS
Complementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...
version of the Z80000.